This article describes how to configure active sampling using a sampling instance and associate that sampling instance to a particular PFE. It includes an example showing the configuration of a sampling instance on an MX480 router with IPv4 and IPv6 interfaces.

Topology

                                      R3
                                      |
                                 <ge-2/3/9>
                          20.1.1.2/30 | 2002::2/64
                                      |
                                      |
                          20.1.1.1/30 | 2002::1/64
                                 <ge-1/3/7>
                                      |
R1 <ge-1/0/0> ---------- <ge-1/3/9>  R2  <ge-1/3/8> ---------------------<ge-0/1/0>  R4 
10.1.1.1/30            10.1.1.2/30        3001::2/64                      3001::1/64

Hardware used: MX-480

FPC 0 REV 08 750-024064 YC3847 MS-DPC
FPC 1 REV 17 750-021157 YB4434 DPCE 40x 1GE R TX

R2> show version 
Model: mx480
JUNOS Base OS boot [12.2R1.8]

Configuration

On R2: Sampling*
[edit chassis]
lab# show 
fpc 1 {
    sampling-instance a1;
}

[edit interfaces]
lab# show 
sp-0/0/0 {
    unit 0 {
        family inet;
    }
}
sp-0/1/0 {
    unit 0 {
        family inet6;
    }
}
lab# show interfaces ge-1/3/7 
unit 0 {
    family inet {
        address 20.1.1.1/30;
    }
    family inet6 {
        address 2002::1/64;
    }
}
lab# show interfaces ge-1/3/8  
unit 0 {
    family inet6 {
        filter {
            input v6-sample; 
        }
        address 3001::2/64;
    }
}
lab# show interfaces ge-1/3/9  
unit 0 {
    family inet {
        filter {
            input v4-sample;
        }
        address 10.1.1.2/30;
    }
}

[edit forwarding-options]
lab# show 
sampling {
    instance {
        a1 {
            input {
                rate 1;
                run-length 0;
            }
            family inet {
                output {
                    flow-server 10.1.1.2 {
                        port 2055;
                        version9 {
                            template {
                                v4;
                            }
                        }
                    }
                    interface sp-0/0/0 {
                        source-address 1.1.1.1;
                    }
                }
            }
            family inet6 {
                output {
                    flow-server 10.1.1.2 {
                        port 2055;
                        version9 {
                            template {
                                v6;
                            }
                        }
                    }
                    interface sp-0/1/0 {
                        source-address 1.1.1.1;
                    }
                }
            }                           
        }
    }
}

[edit services]
lab# show 
flow-monitoring {
    version9 {
        template v4 {
            flow-active-timeout 30;
            flow-inactive-timeout 30;
            ipv4-template;
        }
        template v6 {
            flow-active-timeout 30;
            flow-inactive-timeout 30;
            ipv6-template;
        }
    }
}

[edit firewall]
lab# show 
family inet {
    filter v4-sample {
        term 1 {
            then {
                sample;
                accept;
            }
        }
    }
}
family inet6 {
    filter v6-sample {
        term 1 {
            then {
                sample;
                accept;
            }
        }
    }
}

Verification

For v4 Traffic

Ping from R1 to R3 and check the flows on R2:

For v6 Traffic

Ping from R4 to R3 and check the flows on R2:

Troubleshooting

• Example: Sampling Instance Configuration
• Configuring Sampling Instances